I just got back from activating a WFF park. I wanted to tag the log for each one with the park ID listed in the awards tab. For each individual log entry, I had to pick the same park (KFF-1829). Is there a way to make Log4OM keep the park name there, like it does with the date, time or frequency?

No Roger,
Unlike SOTA and IOTA the ADIF specification does not at this time have a field for the activators location reference

The best thing to do is use the bulk editor to add the activator reference to the comments field then perhaps eventually if the ADIF field becomes available those references can be moved across - Like 'My WWFF Ref KFF-1829'

Terry, Logsearch, (the WWFF award site) does have a place for the Activators reference.
Roger, the Award reference under the Clubs and Awards tab is for entering the reference of the other person, not yours, so there is no need to have a lock on that field.
You put your own park reference in Station Info under My Sig (WWFF) and My Sig Info (WWFF-xxxx)(whatever your ref no is)
The other contacts park info goes under Extended info & QSL in Sig (WWFF) and Sig Info (WWFF-xxxx) (whatever his reference is)
Then when the log is uploaded to Logsearch you get credit for Activation and Park to Park Awards.